1. Field of the Invention
This invention relates to a DC multi-pole electrodynamic device, more particularly to a cup type DC multi-pole coreless motor.
2. Description of the Prior Art
The armatures for electrodynamic devices, such as cup type DC coreless motors, now commercially available have such a poor efficiency that the permanent magnet with high magnetic field strength such as those made of alnico or rare earth metal are used especially for a micro motor to compensate for the lower efficiency of the armature. This results in limiting their applications, as well as making the motors more expensive to manufacture.
The problems to be solved, especially for a DC multi-pole motor are: that the multi-pole motor is expensive to manufacture due to difficulties in winding a conductor sequentially on the armature to form armature coils; a large number of motor components such as brushes or additional external connecting lines between coils or commutator segments located symmetrically in the magnetic field in addition to difficulties in the connecting procedure; and, consequently, the difficulties in assembling the components.